title: Mitochondrial and DNA damage in bovine somatic cell nuclear transfer embryos.
abstract: The generation of reactive oxygen species (ROS) and subsequent mitochondrial and DNA damage in bovine somatic cell nuclear transfer (SCNT) embryos were examined. Bovine enucleated oocytes were electrofused with donor cells and then activated by a combination of Ca-ionophore and 6-dimethylaminopurine culture. The H2O2 and ˙OH radical levels, mitochondrial morphology and membrane potential (ΔΨ), and DNA fragmentation of SCNT and in vitro fertilized (IVF) embryos at the zygote stage were analyzed. The H2O2 (35.6 ± 1.1 pixels/embryo) and ˙OH radical levels (44.6 ± 1.2 pixels/embryo) of SCNT embryos were significantly higher than those of IVF embryos (19.2 ± 1.5 and 23.8 ± 1.8 pixels/embryo, respectively, p < 0.05). The mitochondria morphology of SCNT embryos was diffused within the cytoplasm. The ΔΨ of SCNT embryos was significantly lower (p < 0.05) than that of IVF embryos (0.95 ± 0.04 vs. 1.21 ± 0.06, red/green). Moreover, the comet tail length of SCNT embryos was longer than that of IVF embryos (515.5 ± 26.4 μm vs. 425.6 ± 25.0 μm, p < 0.05). These results indicate that mitochondrial and DNA damage increased in bovine SCNT embryos, which may have been induced by increased ROS levels.
authors.affiliation: College of Veterinary Medicine and Institute of Veterinary Science, Kangwon National University, Chuncheon 200-701, Korea.
authors.forename: In-Sun
authors.initials: IS
authors.lastname: Hwang
authors.forename: Hyo-Kyung
authors.initials: HK
authors.lastname: Bae
authors.forename: Hee-Tae
authors.initials: HT
authors.lastname: Cheong
mesh_terms: D000818:Animals; D017209:Apoptosis; D053148:Caspase 3 / Q000378:metabolism; D002417:Cattle; D003124:Colorimetry / Q000662:veterinary; D020552:Comet Assay / Q000662:veterinary; D004249:DNA Damage; D004272:DNA, Mitochondrial / Q000235:genetics* / Q000378:metabolism; D004624:Embryo Transfer / Q000662:veterinary; D004622:Embryo, Mammalian / Q000166:cytology* / Q000196:embryology; D005307:Fertilization in Vitro / Q000662:veterinary; D020287:In Situ Nick-End Labeling / Q000662:veterinary; D053078:Membrane Potential, Mitochondrial; D018613:Microscopy, Confocal / Q000662:veterinary; D008856:Microscopy, Fluorescence / Q000662:veterinary; D008928:Mitochondria / Q000378:metabolism*; D053652:Nuclear Transfer Techniques / Q000662:veterinary*; D017382:Reactive Oxygen Species / Q000378:metabolism*
chemical_list: D004272:DNA, Mitochondrial; D017382:Reactive Oxygen Species; D053148:Caspase 3
keywords: DNA fragmentation; ROS generation; cattle; cellular damage; somatic cell nuclear transfer